/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.seata.server.metrics;

import java.util.List;

import org.apache.seata.config.ConfigurationFactory;
import org.apache.seata.core.constants.ConfigurationKeys;
import org.apache.seata.metrics.exporter.Exporter;
import org.apache.seata.metrics.exporter.ExporterFactory;
import org.apache.seata.metrics.registry.Registry;
import org.apache.seata.metrics.registry.RegistryFactory;
import org.apache.seata.server.event.EventBusManager;

import static org.apache.seata.common.DefaultValues.DEFAULT_METRICS_ENABLED;

/**
 * Metrics manager for init
 *
 */
public class MetricsManager {

	private Registry registry;

	public static final MetricsManager get() {
		return SingletonHolder.INSTANCE;
	}

	public Registry getRegistry() {
		return registry;
	}

	public void init() {
		boolean enabled = ConfigurationFactory.getInstance()
			.getBoolean(ConfigurationKeys.METRICS_PREFIX + ConfigurationKeys.METRICS_ENABLED, DEFAULT_METRICS_ENABLED);
		if (enabled) {
			registry = RegistryFactory.getInstance();
			if (registry != null) {
				List<Exporter> exporters = ExporterFactory.getInstanceList();
				// only at least one metrics exporter implement had imported in pom then
				// need register MetricsSubscriber
				if (exporters.size() != 0) {
					exporters.forEach(exporter -> exporter.setRegistry(registry));
					EventBusManager.get().register(new MetricsSubscriber(registry));
				}
			}
		}
	}

	private static class SingletonHolder {

		private static MetricsManager INSTANCE = new MetricsManager();

	}

}
